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5 Answers
5

Depends what you mean by "require Visual Studio". Your choice of IDE isn't really related to the language used or size of the project, in my opinion, just so long as you're using an editor you feel comfortable with.

If you are looking for editors other than the default Scite that comes with Unity...

If you feel like changing from Javascript to C# or Boo, I find Monodevelop to be very excellent. There are some other suggestions here.

Updated for question update

Absolutely, use an external IDE or text editor. It's all just text files in the end, Unity doesn't offer any additional benefit from using Scite. Pick (or find) an editor you love and use that, it can only possibly make your life better (even on small projects!)

"[MonoDevelop] doesn't offer any additional benefit from using Scite" - That's only true if you don't consider intellisense, intelligent refactoring, integrated debugging, and automatic syntax checking as "additional benefits." Using a text-editor to program is simply unprofessional in this day and age.
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BlueRaja - Danny PflughoeftFeb 1 '14 at 7:01

Visual Studio's primary "benefit" is its project management, build system, integrated debugger, plugins and extensions, and so on. Most of those are not going to work well with Unity, especially a Unity program primarily in JavaScript. The basic editor will still work fine, but Visual Studio is kind of crap at editing compared to things whose main purpose is to edit text, like vim and Emacs.

If your goal is a well-integrated and consistent deployment to your developers, you should probably just use Unity's built-in editor. It's not great, but it's fast, free, and works everywhere.

On the other hand, if your developers have a lot of Visual Studio experience, they can use that if they want. It's just going to be as a text editor, and not as a project manager or compiler or debugger (except for the odd Unity native extension).

As Unity is highly cross platform, I suspect that there is no requirement to use Visual Studio. You should use whatever development tools you're comfortable with. I've learned Vim over the past year and can't recommend it highly enough as an editor. Presumably any code build you would need to do could be accomplished on the command line.

I have been using Monodevelop and VS2010 for Unity game development for several months now. MD seems to let me have breakpoints and some minor control but it's all silver lining only, you can only do a play or an edit when you run normally outside mono debug run call.

VS2010 just refuses to synch at all, I couldn't figure out yet how to get the same execution, I'm guessing it's not supported.

Monodevelop needs some getting used to, both for JS and C# I reckon. Going from C++ to JS you probably must be wondering if you are coding or doodling with a crayon by now.

Just do yourself a big favor and go to the preferences for keybindings and change it all to the ones you are used to. Hitting CTRL-SHIFT-HOME for a backwards indent on a keyboard requiring FN left arrow is a whopping 4 key combo. Even mortal combat was easier to learn than that.

In short: VS2010, possible but no feedback or breakpoints, Monodevelop, takes some getting used to but it 500 times better than unitron/uniscite , that's just plain notepad--